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Chapter




                                                                                           4






                                                Plane Stress Analysis






                                            Determination  of  deformation  and  stresses  for  two-
                                 dimensional  elasticity  problems  is  rather  difficult  by  using  the
                                 conventional approach.  The finite element method alleviates such
                                 difficulty especially for problems with complicated geometry.  This
                                 chapter  begins  with  the  governing  differential  equations  of  the
                                 plane stress problem.  Finite element equations and their element
                                 matrices are derived for a simple triangular element.  ANSYS with
                                 its Workbench are employed to solve for solutions of examples in
                                 both academic and application problems.


                                 4.1   Basic Equations

                                     4.1.1  Differential Equations

                                            The equilibrium conditions at any point of a membrane
                                 that lies in x-y plane, under in-plane forces with exclusion of body
                                 forces, are governed by the two partial differential equations,
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